She has modeled for magazines such as Vogue, Teen Vogue and Pop Magazine. In 2017, she made her runway debut for Raf Simons' Calvin Klein Collection, then walked for fashion houses such as Marc Jacobs, Burberry, Alexander Wang, Coach, Prada, Chanel, Fendi, Moschino, and Versace, alongside her mother, during 2018 Spring Fashion Week. She landed her first solo Vogue cover on the February 2018 issue of Vogue Paris. Gerber appeared in Spring 2018 campaigns for Versace, Calvin Klein, Marc Jacobs and Omega. In 2018 she led the campaign for Marc Jacobs Daisy fragrance (alongside model Sofia Mechetner). In 2018 Gerber collaborated with designer Karl Lagerfeld to create the KarlxKaia collection; which was her first collection.